Treating oils in the presence of clay



Patented Aug. 31, 1937 PATENT OFFICE oms 1N 'me PRESENCE or CLAY Reginald E Stratford, Sarnia, Ontario, Canada,

corporation of invention toa-method of utilizing spentclayusedinthe 'stocksJorthepurpose invention.v z; 1:. 1o 1.--One :object'of:

of the spent;

which it contains.

Another object is to promote octane usually obtained zat a ml ir. i

`treatment of lubricating oil bfrimprcving-:the cracking vbe'understood from the the soie figurent which is a `for. carrying out the e invention isfthe utilization clayusedin-the treatment of lubricating 0118 methetwthz the'so-called soakage oil the cracldng of -of the 4spent clay and to number gasoline than is given Vtemperature of A hfmvtheanve-ntion is to improve 20 the color .stability-fof :the

* using-spent clay cracked naphtha by lubricating oil treatment in the fractionating tower ot the rerun still, and further, applyingI-therclay which has been used in said tower tothe a-cracked aspro'dwe stable crackedn'aphthafis obtained inthe' ypromotion of cracking to In this way a color Y with a high with the clay or it may and asphaltic material as to produce a sowhich is then admixed `iIt"'v|rill be, therefore, ap-

4invention may be carried cations, some of which A consci method in smeren mman wilicnthe lubricating ou stock aihicklayer o! coarse clay, or

'isz'admixed and heated tun divided4 clay,

- as used in the s'pecication an treated.

0il Development Com- Delaware pucsuonretmy zi, 1935, sum No. '1,521 "z cmms. (ctms-55) oil. In all these modiilcations, either natural clay` such as iullers earth or so-called acid treated clay such as nltrol is used. The term clay d claims is intended to include any such adsorbent clay, natural or which is used in the decolcrization treatment oi.' lubricating oils. For our purposes it is preferable tc-use the inely divided spent clay from a contact ltration or contact reduction process. In 'all cases the spent claycontains an "10 appreciable amount of lubricating oil stock with so-called soakage oil, which is a good raw material for cracking and will be thus utilized when the spent clay is added to the cracking stock.

In the preferred method of my process, however, I do not add the spent clay directly to the cracking stock, but I introduce the same into the tower of the rerun still, in which the cracked naphtha is redistilled to obtain a finished gasoline. The spent clay has the eiiect of stabilizing the color of the naphtha. After passing through the tower the spent clay is admixed with the charging stock and passed through the cracking system in admixture with the oil.

Any of the known cracking methods may be used including the method in which all the cracking is carried out in.the heating and cracking coil and the so-called tube and tank method in which the cracking is carried out by passing the charge through the heating coil into an enlarged reaction drum, the so-called soaking 'I'he pressure may be atmospheric or higher. Usually it is preferable to operate my process under a pressure of several hundred pounds per square inch. The temperature at which the cracking is carried out may vary, say from about '150 F. to 1000"` F., although higher cracking temperatures may also be used. In carrying out my process the cracked oil and the admixed clay are usually passed into a so-.called separator in which the tar is obtained as a liquid residual product while the naphtha and the gas oil are passed as an overhead vapor product into a iractionating zone in which the gas oil is" separated from the naphtha. This gas oil isusually returned to the cracking as cycle stock. The liquid tar contains most of the clay in suspension. This tar is cooled to a temperatu're below its flash point and then left to settle, whereby the clay is separated from the tar proper. Usually there is some coke formed inthe 5 reaction chamber. This coke will also contain Referring described in coni erating the apparatus. The oil cracked now to ligure, the same'will be unctionvith the method oi opsuch Q5.

as gas oil is charged from the storage tank I to the accumulator 2 and thence through line 3 and heating coil 4 to the soaking drum 5. Spent clay obtained in treating lubricating oil stock is 5 passed from bin 6 by means of line 6a into the mixing tank 1 into which a certain amount of a cycle stock is alsodischarged, as will be de- I scribed hereinafter. From the mixing tank the slurry of oil and clay is discharged through line 8 into line 3 where it meets the oil from the accumulator 2. The oil and clay pass through the cracking system as described above. From the soaking drum 5 the oil and clay slurry together with the vapors and gases are discharged into the separator 9 from which the tar and the spent clay are removed through the bottom line and cooler I0 into the settling tank II. From the latter, the oil and the clay are separately removed to points of disposal (not shown). The

vapors and gases from the separator are passed o through line I5 into the debutanizing tower I6.

The condensate from towers I2 and I3 consists oi.' cycle stock and maybe discharged directly into the accumulator. vAll or part of the condensate from tower I3 may be removed through cooling coil I la and passed into storage tank Mb to be used as heating oil. Part of this condensate may be used for preparing the clay slurry in mixing tank 1. The naphtha distillate passes through the debutanizing tower I6 into the bubble tower I1, thebottom part of which is connected with a still I8 for the purpose of heating, and vaporization. The bottoms from this still is removed through cooler I9 into the storage tank 20. The still I8 is in vapor connection with the bubble 5 tower I1 by means oi' line 2I. The vapors rising from the bubble tower I1 are passed into the lower part of the clay tower I1a from which latter the vapors are removed through line 22, condensed in condenser 23 and passed into storage tank 24 o as a stable naphtha distillate. Part of this naphtha distillate is discharged through line 25 into the mixing tank 26 into which spent clay from bin 6 is also charged through line 21. The naphtha-clay slurry from mixing tank 26 is then discharged to the upper part of the clay treating tower I1a to ow in counter-current with the vapors coming from bubble tower 'I1. The naphtha-clay slurry from tower I1a is passed into the settling tank 28 from which the heavy naphtha is removed through cooler 29 into the storage tank 30. The spent clay is discharged into container 3| and thence to bin 32, from which it is finally charged through line 33 to the mixing tank 1.

The following example will illustrate my inven- 5 non. A 31.0 A. P. I. Mid-continent gas ou was submitted to cracking in a tube and tank unit with return oi the cycle stock to the cracking. In one case the cracking was carried out as usual and in the other case 1.79# of clay per barrel of fresh feed was added. The conditions of the cracking were identical in the two cases, namely, coil outlet temperature 884 F., pressure on the soaking drum 800# per square inch, the hot enluent from the coil being introduced into the bottom of the soaking drum and taken off at the tcp thereof with the release of pressure. Due to the recirculation of the cycle stock the percentage of the fresh feed in the total feed was 50.3%. The following results were obtained:

v Oil plus clay Oil alone 400 end point distillate, percent by volume.- 49. 4 62. 2 Furnace fuel, percent by volume.. 10. 61 11.85 Tar, percent by volume 32.9 30. l D gas, cubic Ieet per barrel..- l0. '.8. 2 C9 e, percent by weight 0. 44 0.39 .Distillete octane No. C. F. R. M 64.5 59.5 Percent B. S. in tar 0. 37 0. 66 Percent B. S. by extraction 0. 004 0. 060

These results lead to the Aconclusion that the eilect of the clay is a catalytic promotion of the cracking and is somewhat similar to an increase in the cracking temperature. It appears, however, that the use of spent clay produces a higher octane number gasoline than would be expected "for an increase in coil outlet temperature to give invention.

What I claim is:

l. A process for converting relatively high boilin g hydrocarbon oil-into lower boiling products including hydrocarbons'sultable for use as motor fuel, which comprises admixing a clay previously spent in the decolorization treatment of lubricating oils with a uid stream o! said relatively high boiling oil, passing said mixture through an elongated zone of restricted cross section wherein vit is heated to an oil cracking temperature, maintaining the mixture at cracking temperature for a period sumcient to produce the desired conversion of said oil, introducing the cracked prodacts into a separating zone wherein vapors separate from liquid residue, withdrawing said residue from the process and preventing .its return to the heating zone, fractionating said vapors to separate a lower boiling fraction including motor fuel constituents and a reilux condensate, subjecting products from said lower boiling fraction while essentially in vapor form to contact with an adsorbent clay previously spent in the decolorization treatment of lubricating oils and .thereafter utilizing said clay last mentioned as at least a portion of the clay introduced' into the iluid stream of oil prior to its passage through the heating zone.

2. A process for converting relatively high boiling hydrocarbon oil into lower boiling products including hydrocarbons suitable for use as motor fuel which comprises admixing a clay slurry with a uid stream of said relatively high boiling oil,y

passing said mixture through an elongated zone of restricted cross section wheren it is heated to an oil cracking temperature, maintaining the mixture at cracking temperature for a period sufilcient to produce the desired conversion ot said oil, introducing the cracked products into a separating zone wherein vapors separatev from liquid residue, withdrawing said residue from the process and preventing its return to the heating zone,

fractionating said vapors to separate a lower boiling fraction including motor fuel constituents and a reflux condensate suitable for use as clean cracking stock, subjecting products from said lower boiling fraction while essentially in vapor form to contact with a slurry of hydrocarbon oil and adsorbent clay previously spent in the decoiorization treatment of lubricating oils, sepa.- rating said adsorbent clay from the treated low 3 boiling products, admixing said separated clay with at least a portion of said redux condensate to produce a. second slurry and using slurry thus obtained as at least a. portion of the slurry which is introduced into the iiuid stream of oil prior to its passage through the heating zone.

REGINALD K. STRATFORD. 

